Divya Pandey

Carbon footprint: current methods of estimation

Increasing greenhouse gaseous concentration in the atmosphere is perturbing the environment to cause grievous global warming and associated consequences. Following the rule that only measurable is manageable, mensuration of greenhouse gas intensiveness of different products, bodies, and processes is going on worldwide, expressed as their carbon footprints. The methodologies for carbon footprint calculations are still evolving and it is emerging as an important tool for greenhouse gas management. The concept of carbon footprinting has permeated and is being commercialized in all the areas of life and economy, but there is little coherence in definitions and calculations of carbon footprints among the studies. There are disagreements in the selection of gases, and the order of emissions to be covered in footprint calculations. Standards of greenhouse gas accounting are the common resources used in footprint calculations, although there is no mandatory provision of footprint verification. Carbon footprinting is intended to be a tool to guide the relevant emission cuts and verifications, its standardization at international level are therefore necessary. Present review describes the prevailing carbon footprinting methods and raises the related issues.

Carbon Footprint Estimation in the Agriculture Sector

The term “carbon footprint” has evolved as an important expression of greenhouse gas (GHG) intensity for diverse activities and products. Widespread public acceptance and the ease of conveying information about GHG intensity with this term has also attracted scientists and policy makers to review and refine its calculations. Standard methods for carbon footprinting have been prepared, and sector-specific standards are under development. These standards direct the procedures to carry out carbon footprinting through life cycle assessment in conjunction with GHG accounting, classifes activities into three tiers based on the order of emissions. Agriculture is the largest contributor to anthropogenic emissions of greenhouse gases, so the quantification of different agricultural practices is essential for identification of more sustainable practices. Carbon footprinting has potential as a tool for assessing and comparing GHG performances of different agricultural products along with identification of points to improve environmental efficiencies. Case studies on the application of carbon footprinting to cultivation practices are increasing in the scientific literature, but the majority of studies do not comply with the standard three-tier methodology. This leads to nonuniformity among different studies and their comparisons. Hence, a standard guideline addressing carbon footprinting specifically for agriculture is essential for the effective application of this tool in the quantification of GHG intensity, mitigation of global warming, and adaptation against future climate change scenarios.

Deterioration of rhizospheric soil health due to elevated ultraviolet-B

Enhancements in ultraviolet-B radiation (UV-B) due to stratospheric ozone depletion affect biological forms directly and indirectly. To investigate how belowground processes are affected under increased UV-B, a field experiment with mung bean cultivars (HUM-1 and HUM-12) was conducted. The responses of selected soil enzymes (β-glucosidase, cellobiohydrolase, polyphenol oxidase, glycine aminopeptidase, and phosphatase), microbial biomass C and N were assessed in rhizospheric and non-rhizospheric zones, along with measurements of phenol and flavanoid contents in roots and leaves. Test plants were exposed to two UV-B levels: (1) UVB, simulating 20% stratospheric O3 depletion; and (2) UV0, the ambient UV-B. Elevated UV-B depressed shoot biomass by 24.8 and 15.9% and root biomass by 43.7 and 38.4% in cv. HUM-1 and HUM-12 compared with UV0. Although elevated UV-B caused an increase in phenol and flavonoid contents in leaves and roots, a reduction in the number of root nodules (32.4 and 24% in HUM-1 and HUM-2, respectively) and their fresh weight (27 and 23% in HUM-1 and HUM-2, respectively) was observed. Elevated UV-B caused microbial activity to shift from the rhizosphere to non-rhizosphere as indicated by increased microbial biomass N and soil enzyme activities in this zone.

Phytoremediation of metals using lemongrass (Cymbopogon citratus (D.C.) Stapf.) grown under different levels of red mud in soil amended with biowastes

ABSTRACT Due to hostile condition of red mud (RM), its utilization for vegetation is restricted. Therefore, RM with biowastes as soil amendment may offer suitable combination to support plant growth with reduced risk of metal toxicity. To evaluate the effects of RM on soil properties, plant growth performance, and metal accumulation in lemongrass, a study was conducted using different RM concentrations (0, 5, 10, and 15% w/w) in soil amended with biowastes [cow dung manure (CD) or sewage-sludge (SS)]. Application of RM in soil with biowastes improved organic matter and nutrient contents and caused reduction in phytoavailable metal contents. Total plant biomass was increased under all treatments, maximally at 5% RM in soil with SS (91.4%) and CD (51.7%) compared to that in control (no RM and biowastes). Lemongrass acted as a potential metal-tolerant plant as its metal tolerance index is >100%. Based on translocation and bioconcentration factors, lemongrass acted as a potential phytostabilizer of Fe, Mn, and Cu in roots and was found efficient in translocation of Al, Zn, Cd, Pb, Cr, As, and Ni from roots to shoot. The study suggests that 5% RM with biowastes preferably SS may be used to enhance phytoremediation potential of lemongrass.

Assessment of soil quality under different tillage practices during wheat cultivation: soil enzymes and microbial biomass

Microbial processes, particularly enzyme activities, play crucial functional roles in soil ecology, hence serving as sensitive indicators of soil quality. We assessed the temporal dynamics of microbial biomass and selected soil enzymes (β-d-glucosidase, cellobiohydrolase, polyphenol oxidase, urease, glycine-aminopeptidase and alkaline phosphatase) during wheat cultivation, under four different tillage practices in the rice–wheat system. The four practices involved conventional tilling of soil before cultivating each crop (CTR-CTW); no tilling before cultivating rice but conventional tillage before wheat (NTR-CTW); conventional tilling before cultivating rice but no tilling before wheat (CTR-NTW) and no tilling before cultivation of each crop (NTR-NTW). Microbial biomass and activities of hydrolytic enzymes increased under NTR-NTW followed by CTR-NTW and NTR-CTW with respect to the conventional practice CTR-CTW, thus reflecting improvement in microbial activities with reduced tillage frequency. Enzyme activities generally depended on soil moisture and temperature, but nature of relationships varied among different practices. Nutrient demand appeared to be the strongest driver of alkaline phosphatase and urease, and soil temperature for glycine-aminopeptidase. Under CTR-CTW, activities of most of the extracellular enzymes were related with β-d-glucosidase or urease, but such relations altered under rest of the practices. The study showed that extracellular soil enzymes respond sensitively to tillage practices as well as environmental variables, particularly soil temperature and moisture and hence can serve as a sensitive indicator of changes in soil processes. Considering improvement in microbial biomass and enzymatic activities as indicators of better soil quality, adoption of no tillage apparently improved soil quality. Still, more number of field studies are required under tillage managements to explore the relationships between different enzyme activities and environmental factors.

Increasing social welfare by taxing pesticide externalities in the Indian cotton sector

BACKGROUND Pesticide use in the Indian cotton industry has decreased with the introduction of Bt cotton, but rates are still high in comparison with other countries. The adoption of alternative strategies, such as integrated pest management, has been slow, even though benefits are potentially high, more so if the full costs of the external effects of the technologies are taken into account. In order to estimate true societal benefits of different strategies, we compare their external costs and economic performance under external cost taxation, using a state-of-the-art partial equilibrium model of the Indian agricultural sector. RESULTS Pesticide externalities lower social welfare in the Indian cotton sector by

Global warming potential and sustainable management of three land uses in Varanasi

US 400-2200 million, depending on the technologies employed. A full internalisation reduces producer revenues by

Bioprocessing of Metals from Packaging Wastes

US 100 ha-1 if only Bt cotton is used, and by

Electrophoretic Separation of Humic Acids Isolated from Tropical Soils Through Modified Denaturing Polyacrylamide Gel Electrophoresis

US 30 ha-1 if IPM is another option. Consumers do not start to lose surplus until 20-70% are internalised, and losses are smaller if all technologies are available. CONCLUSION External pesticide costs can be internalised partially without substantially affecting consumer surplus while still increasing social welfare, but producers need to have access to and the knowledge to employ all available cotton production technologies to minimise losses.

Carbon Footprints of Rice Cultivation under Different Tillage Practices in Rice-wheat System

Purpose – Varanasi, an ancient city has witnessed the conversion of forest into agricultural lands. The high urbanization rate along with affluent lifestyle is adding another category of land use, i.e. landfill. Such land use changes significantly affect the fluxes of greenhouse gases (GHGs) from soil thus contributing to global warming. The purpose of this paper is to quantify the global warming potential (GWP) of the three land uses in Varanasi city taking into consideration CH4 and CO2.The paper also highlights the land use pattern of Varanasi. Design/methodology/approach – Sites representing land uses under forest, agriculture and landfill were identified in and around the city and measurements of GHG fluxes were conducted periodically using closed static chambers. The GWP from each land use was calculated using the standard formula of IPCC (2007). Findings – Landfill was found to be the land use with the highest GWP followed by agriculture. GWP from forest was negative. The study indicated that conve...